Comments

you could change anything in the source code - it is released under an open source license. Anyway the current available windows installer is in sync with the released source code.
The current community edition of mendelson AS4 does not support ENTSOG V3 - this is currently only supported by the commercial edition. We will release the next open source version soon - this will support ENTSOG V3 then.

I downloaded the source from https://sourceforge.net/projects/mendelson-as4/files/ , and I am now able to compile and launch the software, but I get a crash at startup related to the init of the local db (SQLScriptExecutor: Resource /sqlscript/config/CREATE.sql not found).
This script is not provided in the source.

Regarding the availability of ENTSOG V3 in the open source version, I find a discrepancy from what you are saying.
From UsageProfileEntry.java:

Well, after seeing your message, I looked a bit everywhere, and finally found it by opening the jar provided with the compiled version, and extracting the ressources.
I still have a lot of issues and am unable to run the project, but it's a progress.
Thanks,